A study was undertaken to evaluate the safety and immunogenicity of a combination vaccine (TETRAMUNE) of conjugate Haemophilus influenzae type b (Hib) vaccine (HibTITER) and DTP (Diphtheria, Tetanus and Pertussis) vaccine. A total of 93 healthy children were randomized to receive either TETRAMUNE (combined group), or DTP and HibTITER administered concurrently (separate group) in separate syringes at approximately 2, 4 and 6 months of age in Taiwan. Serologic responses were largely comparable between the two vaccine groups; almost all subjects were seropositive to Hib PRP (polyribosylribitol phosphate) and were protected against diphtheria and tetanus after 2 doses of vaccine and mounted prominent responses to the components of Bordetella pertussis. Subjects in the combined group did not experience more adverse reactions compared with those in the separate group. We concluded that HibTITER was highly immunogenic and safe when administered concurrently with DTP vaccine to Taiwanese children. TETRAMUNE was also safe and immunogenic and might reduce the number of injections to achieve the same protection.